Germany has opened a war crimes investigation against an 87-year-old Philadelphia man it accuses of serving as an SS guard at the Auschwitz death camp, the Associated Press has learned, following years of failed U.S. Justice Department efforts to have the man stripped of his American citizenship and deported.

Johann "Hans" Breyer, a retired toolmaker, admits he was a guard at Auschwitz during World War II, but told the AP he was stationed outside the facility and had nothing to do with the slaughter of 1.5 million Jews and others behind the gates.

The special German office that investigates Nazi war crimes has recommended that prosecutors charge him with accessory to murder and extradite him to Germany for trial on suspicion of involvement in the killing of at least 344,000 Jews at the Auschwitz-Birkenau death camp in occupied Poland.

The case is being pursued on the same legal theory used to prosecute late Ohio autoworker John Demjanjuk, who died in March while appealing his conviction in Germany on charges he served as a guard at the notorious Sobibor death camp, also in occupied Poland.

The conviction was not considered legally binding because Demjanjuk died before his appeals were exhausted. But prosecutors maintain they can still use the same legal argument to pursue Breyer. Under that line of thinking - even without proof of participation in any specific crime - a person who served as a death camp guard can be charged with accessory to murder because the camp's sole function was to kill people.

Authorities in the Bavarian town of Weiden, who have jurisdiction, are currently trying to determine whether the evidence is sufficient for prosecution. A German official working on the case confirmed that Breyer was the target of the probe; he spoke on condition of anonymity.

Breyer acknowledged in an interview in his modest row house in northeastern Philadelphia that he was in the Waffen SS at Auschwitz but that he never served at the part of the camp responsible for the extermination of Jews.

"I didn't kill anybody, I didn't rape anybody - and I don't even have a traffic ticket here," he said. "I didn't do anything wrong."

For more than a decade, the Justice Department waged court battles to try to have Breyer deported. They largely revolved around whether Breyer had lied about his Nazi past in applying for immigration or whether he could have citizenship through his American-born mother. That legal saga ended in 2003, with a ruling that allowed him to stay in the United States, mainly on the grounds that he had joined the SS as a minor and could therefore not be held legally responsible for participation in it.

Weiden prosecutors, who were chosen because the office is nearest where Breyer last lived in Germany, say it could take several months before deciding whether to file charges.